When Cynthia Carroll was appointed to lead Anglo American last week she joined an exclusive group as only the third woman to head one of Britain's FTSE 100 companies. However, investors reacted to the announcement by selling the mining company's shares, pushing them down on the day and suggesting that the City was uncomfortable with the idea. The fact that it remains unusual and even alarming to appoint a woman to run a top business reflects the 19th-century attitudes that still prevail in many of Britain's boardrooms. Most leading companies are run by a self-perpetuating elite of middle-aged white men who recruit in their own image and find women - not to mention ethnic minorities - an exotic choice of colleague.

The under-representation of women and, even more so, ethnic minorities in the top ranks of business is shameful, not just in Britain, but in much of the developed world. Before Ms Carroll's appointment, the only two women in charge of FTSE 100 companies were Dame Marjorie Scardino at Pearson, the publishing company, and Dorothy Thompson at Drax, the power operator. The situation is getting worse rather than better; there are only 12 female executive directors at FTSE 100 companies, compared with 20 last year. There are 90 women serving as non-executive directors, but more than a quarter of FTSE 100 firms have no female directors.

While half of graduate recruits to the business world are women, the proportion reaching senior levels falls to 30%, and to just 15% in executive roles. This is no reflection of women's unwillingness to put in the hours: a report this week by the Institute of Directors looked at 1,000 companies and found that female directors worked longer hours for less pay than their male colleagues.

Yesterday the London Business School launched the Lehman Brothers Centre for Women in Business - yet another initiative funded by the investment bank - to find out why women are failing to break through the so-called glass ceiling. Professor Lynda Gratton, who runs the centre, says she wants to call on 150 business leaders to help draw up industry standards for promoting women and creating a working environment that breaks away from the traditional male-dominated model. However, we have been here before. Three years ago the Higgs review of corporate governance launched an initiative to encourage a more diverse range of non-executive directors into the boardroom, suggesting recruiters fish in a wider pool for independent board members. This has, however, largely not happened.

Part of the problem for women is that many networking and social opportunities to build the contacts that help them advance in an organisation are focused around predominantly male pursuits such as golf and drinking sessions. Women do not always push themselves forward either. One leading chief executive told me recently that women do not posture and show off in meetings as men do, believing that if they are competent and do their job well, they will get on. However, that does not necessarily get them noticed. In a competitive environment, rivals will focus on any perceived weakness to get a leg up the corporate ladder, and women can suffer from their lack of profile. It is no accident that many top businesswomen in Britain are Americans, who can be more aggressive in promoting themselves.

Men often focus on women's family commitments as reasons for them bowing out of the race for the top. But there is no shortage of ambitious women.

The business world is missing out on a lot of talent by not thinking more creatively about how to harness women's ambitions in the boardroom. After all, in many cases, the vast majority of customers served by these companies are women, and it is surely damaging to the business that they are not represented in the top ranks. Tesco, for example, Britain's biggest private-sector employer, has a predominantly female workforce and customer base, but not one female executive director. It is the same at Marks & Spencer.

The dearth of women in the corporate upper echelons means the business world is lagging a long way behind progress made by women in politics and the public sector. So far there is no talk of legislation, but that is what Norway has done - companies listed in Oslo have another 12 months to ensure that women hold 40% of board positions or be threatened with closure. What I can't understand is why investors do not put more pressure on boards to recruit more women, since there is a hard business case to be made for it. That could be because most of them are men as well. The solution to getting more women into top business jobs is complex and requires more imaginative thinking than has been seen in the boardroom for some time. But the problem has been discussed for far too long; what we need is action. Businessmen are supposed to be risk takers; it is about time they took some.